title: Facile synthesis of palladium right bipyramids and their use as seeds for overgrowth and as catalysts for formic acid oxidation.
abstract: Controlling the shape and thus facets of metal nanocrystals is an effective way to enhance their performance in catalytic reactions. While Pd nanocrystals with a myriad of shapes have been successfully prepared with good uniformity and in high yield, Pd right bipyramids (RBPs) that have a singly twinned structure have been elusive. We report a facile route based on polyol reduction for the synthesis of Pd RBPs with purity >90% and sizes controlled in the range 5-15 nm. The success of our synthesis relies on the use of iodide ions to manipulate the strength of an oxidative etchant and selectively cap the Pd{100} facets. The as-prepared RBPs could serve as seeds to generate a set of Pd nanocrystals with novel shapes and structures. The RBPs also exhibited enhanced catalytic activity toward formic acid oxidation, with a current density 2.5 and 7.1 times higher than those of the single-crystal Pd nanocubes (which were also mainly covered by {100} facets) and commercial Pd black, respectively.
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States.
authors.forename: Xiaohu
authors.initials: X
authors.lastname: Xia
authors.forename: Sang-Il
authors.initials: SI
authors.lastname: Choi
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Herron
authors.forename: Ning
authors.initials: N
authors.lastname: Lu
authors.forename: Jessica
authors.initials: J
authors.lastname: Scaranto
authors.forename: Hsin-Chieh
authors.initials: HC
authors.lastname: Peng
authors.forename: Jinguo
authors.initials: J
authors.lastname: Wang
authors.forename: Manos
authors.initials: M
authors.lastname: Mavrikakis
authors.forename: Moon J
authors.initials: MJ
authors.lastname: Kim
authors.forename: Younan
authors.initials: Y
authors.lastname: Xia
mesh_terms: D002384:Catalysis; D005561:Formates / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D005561:Formates; D009942:Organometallic Compounds; C030544:formic acid; D010165:Palladium